Field of Disclosure
The present disclosure is generally related to an adjustable pedal assembly of a vehicle, and, more particularly, a variable ratio mechanism for the adjustable pedal, such as a pedal in a brake pedal assembly, whose position can be adjusted while maintaining a constant ratio.
Description of Related Art
Actuating assemblies for operating input elements of vehicles are well-known and include assemblies such as pedal assemblies and hand lever assemblies. A pedal, such as a brake pedal, is mounted to a dash panel in a vehicle so as to provide a driver easy access and manipulation via his/her foot. For example, known brake pedal assemblies include a pedal arm having one end that is pivotally mounted to a mounting structure (e.g., a bracket) provided in the vehicle to enable pivotal movement of the pedal arm about an operating pivot axis. The pedal arm includes an input connector in the form of a booster pin. This booster pin operatively connects to a master cylinder or brake booster push rod that is configured to actuate the master cylinder of the vehicle brake system for purposes of selectively engaging or disengaging the vehicle's brakes. The booster pin is positioned between the operating pivot axis of the pedal arm and a pedal foot pad at an end of the pedal arm opposite the end of the operating pivot axis.
The pedal assembly can have a fixed or static relationship between levers. That is, the master cylinder push rod attachment point, i.e., the brake booster pin, and the operating pivot axis of the pedal arm do not move relative to one another during pedal travel. The geometric pedal ratio for a fixed relationship between levers is typically expressed as R=a/b, where a is the distance between the operating pivot axis and the actuation point on the pedal foot pad, and b is the distance between the operating pivot axis and the master cylinder push rod attachment point, i.e., the booster pin.
With the new lines of vehicles and SUVs on the market, and the desire to utilize common components throughout the full range of vehicles (such as the pedal assemblies and the brake boosters), it is desirable to have an adjustable pedal so that persons of various sizes can access and reach the pedal. Some pedal assemblies can have a pedal arm and pad that can be adjusted between a first (e.g., rearward) position and a second (e.g., forward) position. However, movement of the pedal arm and pad between positions tends to alter the geometric ratio between the levers as well as the linear trajectory for movement and brake application.